The first attacks were directed against England in 790; Lindisfarne in Northumbria was the first of many monasteries (including Iona) to be sacked. In the course of time the territory in the north-east known as the Danelaw became a colony. Alfred the Great (d. 901) wrested London from Viking hands and, by building a fleet, had provided some sort of defence for his kingdom of Wessex. Much the same sort of thing was done at Dublin by Brian Boru, king of Ireland. Later invaders, now Christianized and civilized, occupied most of England, so that Canute (d. 1035) could call himself king of England as well as of Denmark and Norway. His fleet is thus described by a chronicler: 'Gold shone on the prows, silver flashed in the variously-shaped ships. So great was the magnificence of the fleet that if its lord desired to conquer any people, the ships alone would have terrified the enemy, before the warriors they carried joined battle.
Meanwhile the VIkings took advantage of the chaos prevailing in Europe after the death of Charlemagne in 814. Their ships appeared in every northern river, and in France the Duchy of Normandy was established in 911.
About the year 862 other Norsemen crossed the Baltic to seize Novgorod and establish a kingdom at Kiev. Moving down the Dneiper, some crossed the Black Sea to Byzantium, where the emperors recruited them as their Varangian Guard. In the middle of the eleventh century the commander of the guard was Harold Hardrada, who made raids on Sicily, where a Norman kingdom was established in 1139. Returning to claim the throne of Norway, he also claimed that of England until another Harold, the son of Earl Godwin, defeated him near York at the battle of Stamford Bridge. This English Harold then marched south to his death at the battle of Hastings in 1066, at the hands of another Norman who used the same type of ship for his invasion as his ancestors had done.
In 872 the Vikings spread north-west to Iceland, which remained a settlement until 1264. Thence they crossed to Greenland, which was abandoned in 1367, possibly on account of malnutrition. In 986 a Greenlander named Bjorni Herjolfsson accidentally discovered America. After hearing the story, Leif Erikson, the son of Erik the Red of Greenland, sailed farther south in 1003 to name Helluland (variously identified as Labrador or Newfoundland), Markland (possibly Nova Scotia), and Vinland, so named because of the wild vines found there, which suggests a location farther south. Such voyages continued until 1024 in round ships called knarrs.
The Viking longship was the most functional warship every built. A longship found at Gokstad, Oseburg, was clinkerbuilt (i.e. with overlapping planks), 76 feet 6 inches long, 17 feet 6 inches wide, 6 feet 5 inches deep, with a draft of only 3 feet. This, combined with the fact that such craft were double-ended and used only a steering oar, enabled them to penetrate far up rivers and to be easily beached. While at sea a single square sail on a 40-foot mast was used, the sixteen oars on each side being reserved for river work, the well-known shields along the gunwhales being placed there for show. A century later some of these ships were said to be 110 feet long with over 30 rowers on each side.
Little is known about their methods of navigation beyond the fact that they had a rudimentary knowledge of astronomy and that latitude sailing was the rule. Ships bound for Greenland were directed to sail due west from a point thirty miles north of Bergen. Since the compass and rudder were still unknown, some sort of dial to take bearings on the Pole star must have been used.
The longship was only efficient for purposes of war. As trade developed, the broader, rounder type of ship evolved into what was later called the cog, so that the famous 'serpent' or 'dragon' ships, with their fearsome figureheads, vanished from the seas.